Various types of display apparatuses (e.g., televisions, computer monitors, etc.) typically use one of two types of display methods—interlaced scan and progressive scan. In both methods, images are divided into several scanning lines. In the interlaced scan method, the odd numbered scanning lines and the even numbered scanning lines are alternatively displayed. The odd numbered scanning lines of the image are referred to as the odd field or top field. The even numbered scanning lines of the image are referred to as the even field or the bottom field. The top and bottom fields are alternatively displayed at a high speed such that a person sees a single composite screen. In the progressive scan method, the image is displayed line by line; namely, all the scanning lines are displayed.
Interlaced scan data may be field based or frame based. The following is an example of frame based interlaced scan data, where “T” represents a top field, “B” represents a bottom field and “t” represents time:Tt, Bt, Tt+1, Bt+1, Tt+2 Bt+2, . . .As shown above, the frame based interlaced scan data includes a top field and a bottom field of an image derived at the same point in time. If the top and bottom fields from the same point in time were combined, then a frame of progressive scan data would be produced. Next, the following is an example of field based interlaced scan data:Tt, Bt+1, Tt+2, Bt+3, . . .In contrast to frame based interlaced scan data, field based interlaced scan data does not include top and bottom fields from the same point in time. Combining top and bottom fields of field based interlaced scan data to create a frame of progressive scan data may result in a poor image, particularly when a large amount of motion in the images is present.
Different video generation devices (e.g., computers, DVD players, video tape players, etc.) typically generate video data according to one of the interlaced scan or progressive scan method. As such, the video generation device may not produce video data according to a method compatible with the scan method expected by a desired display device.